[Solved] Consider this ARM assembly snippet: MOV R0, #0 WFI MOV R1, #1 What happens to the execution flow when the WFI instruction is reached? | ARM Architecture

ARM Architecture - Power Modes

Consider this ARM assembly snippet:

    MOV R0, #0
    WFI
    MOV R1, #1

What happens to the execution flow when the WFI instruction is reached?

AThe processor enters sleep mode and resumes at the next instruction after an interrupt

BThe processor halts and never executes the next instruction

CThe processor immediately executes the next instruction without delay

DThe processor resets and starts from the beginning

Step-by-Step Solution

Solution:

Step 1: Understand WFI behavior in code flow
When the processor executes WFI, it enters a low-power sleep state and pauses execution.
Step 2: Identify when execution resumes
The processor wakes up only when an interrupt occurs, then continues with the next instruction MOV R1, #1.
Final Answer:
The processor enters sleep mode and resumes at the next instruction after an interrupt -> Option A
Quick Check:
WFI pauses until interrupt, then continues [OK]

Quick Trick: WFI pauses execution until interrupt, then continues [OK]

Common Mistakes:

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